An exhaust line assembly is known, for example, from FR 2 966 873. In such an assembly, a driving shaft is heated to high temperature by the exhaust gases flowing in a bypass conduit. For a gas temperature of 850° C., the temperature of the driving shaft reaches 550 to 600° C. at an end of the shaft which is connected to an actuator. A guiding bearing of the shaft, the actuator and a kinematic chain coupling the actuator to the driving shaft must therefore withstand extremely high temperatures.
This has the consequence that the materials used for the bearing and the elements of the kinematic chain have to be chosen for their temperature resistance, but have other defects. It is particularly difficult to eliminate the noise produced during the rotation of the flap. In addition, significant clearances are created at high temperature because of the expansion of the shaft relative to the bearing. There is also gas leakage along the shaft to the outside of the exhaust line.
It is common to use an electric motor to drive the flap. Such actuators typically include a plastic housing, as well as plastic gears. Thus, the motor and its electronics do not support temperatures above 120 or 140° C., depending on the case.
As a result, it is generally necessary to move the output shaft of the actuator away from the driving shaft in order to limit direct thermal conduction. It is also common to add heat shields between the actuator and the valve.
Moreover, the actuator is generally attached to very hot parts of the assembly using tabs. These tabs conduct heat to the actuator. To remedy this problem, it is possible to move the actuator further away. However, this makes the whole assembly less compact and sensitive to vibration.
In this context, the invention aims to propose an assembly in which the problems mentioned above are suppressed or attenuated.